Heterozygosity for a Single Mutation in the ABCC6 Gene May Closely Mimic PXE

Abstract

We assume that all categories established at the 1992 consensus conference correspond to PXE, but that the 5 patients reported herein also have PXE. Homozygous, compound heterozygous, or heterozygous individuals may fulfill only some of the clinical and/or histopathologic consensus criteria of PXE. They cannot be placed into any category. Expressivity is highly variable in carriers of 1 or 2 ABCC6 mutations, and the disease manifestations overlap between both genotypes. Physicians should thus be more cautious with respect to the prognosis when faced with heterozygous relatives of a patient diagnosed with undisputable PXE. Indeed, heterozygotes may uncommonly experience severe ophthalmologic complications. Whether they may also have cardiovascular complications related to or worsened by PXE remains to be determined.